Bukkit/Bukkit — pull request #394 by iffa (2011-10-26 15:21:29+00:00)
Title: Added TreeGrowEvent

Possible uses: cancel natural tree growth for example in nether, make saplings useless (would be fun!)

I also made a quick test plugin: http://pastebin.com/K2KvKQvX

Associated CraftBukkit pull: https://github.com/Bukkit/CraftBukkit/pull/519